After introducing the fluid pump through a large blood vessel into the ventricle and subsequently setting it in operation after expansion of the rotor, the pumping power of a heart can be assisted there considerably for example in humans or can be partially replaced. The therapeutic advantage of such applications resides in an at least partial relief of the heart muscle.
Expandable fluid pumps of this type are known from the state of the art already. For example, a pump emerges from DE 10 059 714 C1 which can be pushed through a blood vessel together with the pump drive. The blood flows there through a cannula, the diameter of which can be expanded and compressed in order to change the flow ratios.
A blood pump, the rotor of which can be compressed and expanded radially, is known from WO 03/103745 A2, different constructions being proposed there in order to achieve the expandability. For example by means of different mutually displaceable parts of the catheter after introduction, compressing of the pump housing and radial widening, associated therewith, can be effected. On the other hand, by rotating a drive shaft relative to a wire located in the catheter, the possibility is disclosed of producing a helix structure of the wire, the wire carrying in addition a membrane which forms a rotor blade after assuming the helix structure.
In addition, a rotor structure having a plurality of blades which are rigid per se and articulated pivotably on a central part is known from the document, said blades being deployed during operation and hence producing a fluid pressure.
A pump is known from EP 0 768 900 B1, in which rotor blades are articulated on a shaft within a pump housing in such a manner that they can be folded against the shaft in the inoperative state and, during operation, can be deployed perpendicular to the shaft in order to convey the fluid.
From US 2006/0062672 A1, a rotor of a fluid pump is known with blades that are pliably fixed to a hub and that are deployed by the fluid counterpressure generated by initial rotation of the rotor.
It is common to the known state of the art that rotor blades of a pump are pivoted either by means of a pivot mechanism for expansion or by fluid counterpressure during rotation or are formed by a mechanical device in the manner of a Bowden cable or the like only for expansion of the pump.
The object underlying the present invention with the background of the state of the art is to produce a fluid pump having a rotor which can be compressed with respect to the diameter thereof, which is built as simply as possible constructionally, which preferably comprises biocompatible materials like the pump housing surrounding it, the expansion and compression of which housing can be effected as simply as possible and which has the necessary reliability during operation.